1. Field of the Invention
The present invention relates to hand wrenches and in particular to an impact ratchet wrench which functions as a normal hand-operated ratchet wrench and has the additional impact feature enabling a hammer to be used with the invention to loosen a nut or a bolt.
2. Description of the Prior Art
Anyone who has ever used a wrench can understand the frustration of trying to loosen and remove a bolt or nut that is stuck, particularly if it is rusted or painted stuck. Sometimes even using a long lever arm to turn the wrench is not enough.
Very often the bolt or nut is stripped by attempting to loosen it making the task even more difficult, often requiring other types of gripping tools.
Sometimes lubricants, solvents or chemical rust removing compounds or even Coca Cola(copyright) can be used to loosen a bolt or nut that is rusted stuck, but it often takes a while for these liquids to work on the rust, and sometimes even that doesn""t work.
Impact wrenches provide a more powerful approach to loosening nuts or bolts by applying a high impact force directly applied to the nut or bolt head. Some of these devices are very elaborate and often much more expensive than conventional wrenches. Often a power supply of some kind is needed to operate them.
There have been some attempts to provide hand-operated wrenches with impact means for loosening nuts and bolts.
U.S. Pat. No. 6,006,634, issued Dec. 28, 1999 to Byers, provides a socket wrench with a hand-powered impact drive with a pivotal connection between the head and the ratchet mechanism to enable an impact force to the socket when the handle is pivoted rapidly forcing an element to strike the head to force the head to rotate and includes a releasable lock to prevent relative movement of the head and the ratchet mechanism for using the socket wrench in the conventional manner.
U.S. Pat. No. 6,085,621, issued Jul. 11, 2000 to Nezigane, shows a ratchet wrench with a sliding weight on the handle of the wrench and a pivot connection between a small handled head portion of the wrench and the long handled gripping portion. With the two handle portions positioned at approximately right angles relative to each other and the head of the wrench engaged on a bolt or nut, the user may slide the weight down the long handle of the gripping portion to impact a protruding ridge on the long handle which causes an impact force driving at a right angle to the short handle to release a tight nut or bolt or to tighten a nut or bolt.
U.S. Pat. No. 4,474,091, issued Oct. 2, 1984 to Russ, claims a tap wrench with a spring-loaded hammer housed within an enlarged portion of the wrench handle. The spring has a ratchet and pawl so that when the spring is wound up and released it causes the hammer to tap repeatedly on the side of the wrench handle in an attempt to loosen a nut or bolt.
U.S. Pat. No. 5,109,739, issued May 5, 1992 to Hull et al., describes a slide hammer tool screwed onto a wrench and positioned at a right angle to the wrench handle engaging the nut or bolt. The sliding weight or hammer is moved rapidly down the handle to loosen a nut or bolt.
U.S. Pat. No. 4,864,902, issued Sep. 12, 1989 to Doorley, is for a socket wrench slugging device wherein an elongated ratchet wrench replacement head has a perpendicular arm with a flat side on the weight at the end of the arm, wherein the arm is struck with a hammer to loosen a nut or bolt.
None of the prior art devices provide an impact wrench that enables striking the ratchet with a sharp hammer and punch type blow directly applied to the teeth of the ratchet to spin the ratchet and free the bolt or nut.
An object of the present invention is to provide an impact ratchet wrench that functions equally well as a box end ratchet wrench and ratchet socket wrench and as an impact wrench.
Another object of the present invention is to provide an impact wrench with a punch the length of the handle which is struck by a hammer to impart a significant tangential force to the ratchet by striking one of the ratchet teeth with the punch to cause the ratchet to tend to spin to release the nut or bolt.
One more object of the present invention is to provide a sizable striking surface at the top of the impact ratchet wrench so that the hammer can be given a full hard swing without the danger of missing the target.
An added object of the present invention is to provide oversize teeth on the ratchet to insure the ratchet will not be damaged by the impact of the punch.
An additional object of the present invention is to provide an impact ratchet wrench which fits variously sized bolts and nuts by using different ratchet heads or variously sized wrench head inserts, or by using differently sized impact ratchet wrenches.
A further object of the present invention is to provide a ratchet wrench which reverses direction by turning over the wrench to the opposite side.
In brief, an impact ratchet wrench has an offset ratchet head and a punch rod running the length of the hollow cylindrical handle of the wrench. The top of the punch rod is elevated above the top of the wrench handle, held up by a spring at the bottom of the punch rod. An impact cap fitting loosely over the top of the wrench handle rests on the top of the elevated punch rod and provides a large target for the hammer to strike.
The impact cap rides on two bolts attached on opposite sides of the top of the wrench handle with the bolts positioned in spiral openings on opposite sides of the impact cap, allowing the impact cap to rotate freely up and down by turning in a spiral.
A spring-loaded striking pin is pivotally attached to the punch rod near the bottom. The spring causes the bottom end of the striking pin to contact one of the teeth of the ratchet.
With the wrench engaging a stuck bolt or nut, hitting the top of the impact cap with a hammer causes the striking pin to strike the ratchet with a sharp impact and cause the ratchet to rotate thereby loosening the bolt or nut.
Normally the ratchet is free to rotate with each ratchet tooth pushing aside the rotatable striking pin as the tooth passes the pin. The pin is then pushed back by the spring to engage the next ratchet tooth. This striking pin may serve as the primary release pin to operate the ratchet.
An advantage of the present invention is that it provides a relatively simple self-contained tool which is an impact wrench and a ratchet wrench enabling normal usage as either a box end ratchet wrench or ratcheted socket wrench. Then when a difficult situation arises with a stuck bolt or nut, the impact ratchet wrench while still engaged on the stuck bolt or nut is simply struck on the top end with a hammer to loosen the bolt or nut which can then be removed by continuing with the wrench action.